<template>
  <div class="app-container">

    <h2 style="text-align: center;">发布新课程</h2>

    <el-steps :active="1" process-status="wait" align-center style="margin-bottom: 40px;">
      <el-step title="填写课程基本信息"/>
      <el-step title="创建课程大纲"/>
      <el-step title="最终发布"/>
    </el-steps>

    <el-form label-width="120px">

      <el-form-item label="课程标题">
        <el-input v-model="courseInfo.title" placeholder=" 示例：机器学习项目课：从基础到搭建项目视频课程。专业名称注意大小写"/>
      </el-form-item>
	
      <!-- 所属分类 TODO -->
     <el-form-item label="课程分类">
        <el-select
          v-model="courseInfo.subjectParentId"
          placeholder="一级分类"
          @change="subjectLevelOneChanged">

          <el-option
            v-for="subject in subjectOneList"
            :key="subject.id"
            :label="subject.title"
            :value="subject.id"/>

        </el-select>

        <!-- 二级分类 -->
      <el-select v-model="courseInfo.subjectId" placeholder="二级分类">
          <el-option
            v-for="subject in subjectTwoList"
            :key="subject.id"
            :label="subject.title"
            :value="subject.id"/>
        </el-select>
      </el-form-item>

      <!-- 课程讲师 TODO -->
      <!-- 课程讲师 -->
     <el-form-item label="课程讲师" v-if="teacherList && teacherList.length">
        <el-select v-model="courseInfo.teacherId" placeholder="请选择">
          <el-option v-for="teacher in teacherList" :key="teacher.id" :label="teacher.name" :value="teacher.id"/>
        </el-select>
      </el-form-item>

      <el-form-item label="总课时">
        <el-input-number :min="0" v-model="courseInfo.lessonNum" controls-position="right" placeholder="请填写课程的总课时数"/>
      </el-form-item>

      <!-- 课程简介 TODO -->
      <!-- 课程简介-->
     <el-form-item label="课程简介">
       <tinymce :height="300" v-model="courseInfo.description"/>
      </el-form-item>

      <!-- 课程封面 TODO -->
      <!-- 课程封面-->
     <el-form-item label="课程封面">

        <el-upload
          :show-file-list="false"
          :on-success="handleAvatarSuccess"
          :before-upload="beforeAvatarUpload"
          :action="BASE_API+'/eduoss/fileoss'"
          class="avatar-uploader">
          <img :src="courseInfo.cover">
        </el-upload>

      </el-form-item>

      <el-form-item label="课程价格">
        <el-input-number :min="0" v-model="courseInfo.price" controls-position="right" placeholder="免费课程请设置为0元"/> 元
      </el-form-item>

      <el-form-item>
        <el-button :disabled="saveBtnDisabled" type="primary" @click="saveOrUpdate">保存并下一步</el-button>
      </el-form-item>
    </el-form>
  </div>
</template>

<script>
	import course from '@/api/edu/course'
	import subject from '@/api/edu/subject'
	import Tinymce from '@/components/Tinymce'
	export default {
		//声明组件
		components:{Tinymce},
		data() {
			return {
				saveBtnDisabled:false,		// 保存按钮是否禁用
				courseInfo: {
					title: '',
					subjectId: '',//二级分类id
					subjectParentId:'',//一级分类id
					teacherId: '',
					lessonNum: 0,
					description: '',
					cover: '/static/1.png',
					price: 0
				},
				courseId: '',
				BASE_API:process.env.BASE_API,		//接口地址
				teacherList:[],	//封装所有的讲师信息
				subjectOneList:[] 	,//一级分类
				subjectTwoList:[]	//二级分类
			}
		},
		created() {
			this.init()
		},
		watch: {		//监听路由
			$route(to, from) { //路由变化的方式，路由发生变化这个方法就会执行
				this.init()
			}
		},
		
		methods: {
			init() {
				//页面一加载就会执行这个方法
				//获取到路由的id值
				if (this.$route.params && this.$route.params.id) {
					this.courseId = this.$route.params.id
					//调用根据课程id查询课程信息的方法
					this.getCourseInfo()
				} else {
					// this.courseInfo = {}
					//初始化所有讲师
					this.getListTeacher()
					//初始化一级分类
					this.getOneSubject()
				}
			},
			
			//根据课程id查询课程信息
			getCourseInfo() {
				//在courseInfo课程基本信息中。包含一级分类id和二级分类id
				course.getCourseInfo(this.courseId).then(response => {
					this.courseInfo = response.data.courseInfo
					//1 先查询所有的分类
					subject.getSubjectList().then(response => {
						//2 获取所有一级分类
						this.subjectOneList =  response.data.twoSubjectList
						
						//3 把所有的一级分类数组进行遍历
						 for (var i = 0; i < this.subjectOneList.length; i++) {
							 //获取每个一级分类
							 var oneSubject = this.subjectOneList[i]
							 //比较当前 courseInfo里面一级分类id和所有的一级分类id
							 if(this.courseInfo.subjectParentId == oneSubject.id) {
								 //获取一级分类中的二级分类
								 this.subjectTwoList = oneSubject.children
							 }
						 }
					})
					//初始化所有讲师
					this.getListTeacher()
				})
			},
			
			//上传封面成功调用的方法
			handleAvatarSuccess(res,file) {
				this.courseInfo.cover = res.data.url
			},
			//上传封面之前调用的方法
			beforeAvatarUpload(file) {
			  const isJPG = file.type === 'image/jpeg'
			  const isLt2M = file.size / 1024 / 1024 < 2

			  if (!isJPG) {
				this.$message.error('上传头像图片只能是 JPG 格式!')
			  }
			  if (!isLt2M) {
				this.$message.error('上传头像图片大小不能超过 2MB!')
			  }
			  return isJPG && isLt2M
			},
			
			//点击某个一级分类，触发change，显示对应的二级分类
			subjectLevelOneChanged(value) {
				//value就是一级分类的id值
				//遍历所有的分类，包括一级和二级
				for (var i = 0; i < this.subjectOneList.length; i++) {
					//每个一级分类
					var oneSubject = this.subjectOneList[i]
					//判断：所有的一级分类id和点击的一级分类id是否一致
					if(value === oneSubject.id) {
						//从一级分类获取里面的所有二级分类
						this.subjectTwoList = oneSubject.children
						
						//把二级分类id值清空
						this.courseInfo.subjectId = ''
					}
				}
			},
			
			//查询所有的一级分类
			getOneSubject() {
				subject.getSubjectList().then(response => {
					this.subjectOneList = response.data.twoSubjectList
				})
			},
			
			//查询所有的讲师
			getListTeacher() {
				course.getListTeacher().then(response => {
					this.teacherList = response.data.items
				})
			},
			
			// 添加课程的方法
			addCourse() {
				course.addCourseInfo(this.courseInfo).then(response => {
					//提示信息
					this.$message({
						type: 'success',
						message: '添加课程信息成功!'
					});
					//跳转到第二步
					this.$router.push({ path: '/course/chapter/'+response.data.courseId })
				})
			},
			
			//修改课程的方法
			updateCourse() {
				course.updateCourseInfo(this.courseInfo).then(response => {
					//提示信息
					this.$message({
						type: 'success',
						message: '修改课程信息成功!'
					});
					//跳转到第二步
					this.$router.push({ path: '/course/chapter/'+this.courseId })
				})
			},
			//判断是修改还是新增
			saveOrUpdate() {
				//获取到路由的id值
				if (this.courseInfo.id) {
					this.updateCourse()
				} else {
					this.addCourse()
				}
			}
		}
	}
</script>

<style scoped>
	.tinymce-container {
		line-height: 29px;
	}
</style>
